1. Field of the Invention
The present invention relates to a method for modifying fiber surfaces to provide fiber having enhanced hydrophilicity and thermal regulative properties.
2. Description of the Related Arts
Due to the inherent nature of polyester polymers and aliphatic polyamide polymers (e.g., nylon), fabrics formed entirely from these polymers tend to exhibit relatively poor moisture absorption and release properties and fail to have sufficient thermal regulative characteristics. Typically, in apparel fabrics, comfort is obtained by blending those polymers with hydrophilic fibers such as cotton and wool, which has been disclosed in U.S. Pat. No. 5,312,667.
It has long been recognized that there are various known methods for enhancing the hydrophilicity of the polymers. Two examples are the preparation of polymers using appropriate hydrophilic co-monomers and the application of hydrophilic add-on agents or coatings (See, for example, JP 09316782 and JP 08109267). However, these prior approaches have not met with widespread acceptance, in particular due to the lack of permanence under repeated laundering conditions.
The graft polymerization of hydrophilic vinyl monomers onto hydrophobic substrates has been described in U.S. Pat. No. 3,297,786 for use with nylon, polypropylene, polyesters and other substances. See, also, for example, U.S. Pat. Nos. 3,252,880 and 3,278,639. The modification of polyester materials using various chemicals to produce hydrophilic groups on fiber surfaces has been described in U.S. Pat. Nos. 4,808,188 and 5,354,815. The drawbacks of this method include the high cost of chemicals, the low production rate and the production of bulk wastewater during the process.
Accordingly, it is desirable to provide a method for modifying fiber surfaces which overcomes the above disadvantages, and which imparts greatly enhanced hydrophilicity to polymer materials to help transport water (sweat) away from the skin or undergarment of the wearer. A further advantage of the method of the present invention is that it can be readily carried out using conventional textile finishing equipment, and the chemicals used in this method can be recovered and reused. Thus, the method is environmentally friendly.
It is therefore a primary object of the present invention to provide a method for modifying fiber surfaces to impart hydrophilicity and thermal regulative properties thereto. The method comprises treating fiber with an alcohol, especially a polyol, and carrying out chemical reaction between said fiber and said alcohol.
In one preferred embodiment of the present invention, an aliphatic polyamide polymer or polyester polymer is provided having enhanced hydrophilicity and thermal regulative properties. The polymer is bonded to a hydroxyl group by using graft polymerization of an alcohol onto a hydrophobic substrate.